1. Field of the Invention
The present invention relates to a semiconductor device manufacturing machine and a method for manufacturing a semiconductor device by using the same manufacturing machine, and more specifically to a vacuum processing apparatus.
2. Description of Related Art
Referring to FIG. 1, there is shown a diagrammatic view illustrating a construction of a semiconductor device manufacturing machine. The shown machine includes a processing chamber 73 in which a predetermined processing is conducted on a semiconductor wafer 100 put on a stage 72 under low pressure, a load lock chamber 76 for loading the semiconductor wafer 100 to the manufacturing machine from an external source, and a feeding chamber 75 affixed in an air-tight manner between the processing chamber 73 and the load lock chamber 76 and having therein a feeding mechanism (manipulator) 74 for feeding the semiconductor wafer 100 to and removing it from a predetermined position within the processing chamber 73. The feeding chamber 75 is alternately put either in an atmospheric pressure or in a predetermined degree of vacuum. The feeding mechanism 74 has at its tip end a holder 77 for holding directly the semiconductor wafer 100 when the feeding mechanism 74 feeds the semiconductor wafer 100. Between the processing chamber 73 and the feeding chamber 75, there is provided a gate valve 78 for partitioning and sealing in an air-tight manner the processing chamber 73 from the feeding chamber 75. Between the feeding chamber 75 and the load lock chamber 76, there is provided another gate valve 79 for partitioning and sealing in an air-tight manner the feeding chamber 75 from the load lock chamber 76. Furthermore, the load lock chamber 76 has still another gate valve 79 for partitioning sealing in an air-tight manner the load lock chamber 76 from a space external to the machine.
Now, operation of the above mentioned semiconductor device manufacturing machine, namely, a method for manufacturing the semiconductor device by using the above mentioned semiconductor device manufacturing machine, will be described.
First, the gate valve 80 is opened, and a semiconductor wafer 100 is set in the load lock chamber 76 at the atmospheric pressure. Thereafter, the gate valve 80 is closed, and then, the gate valve 79 is opened, so that the feeding chamber 75 which was at a predetermined vacuum level, becomes the same pressure as that of the load lock chamber 76, namely near to the atmospheric pressure. In this condition, the feeding mechanism 74 is operated to hold the semiconductor wafer 100 in the load lock chamber 76 by the holder 77 and to move it into the feeding chamber 75.
Thereafter, the gate valve 79 is closed, and the feeding chamber 75 is evacuated to the predetermined vacuum level. Then, the gate valve 78 is opened, and the feeding mechanism 74 is operated again, to move the semiconductor wafer 100 held by the holder 77, into the processing chamber 73, and to put the same on the stage 72. After the semiconductor wafer 100 is put on the stage 72, the holder 77 is retracted into the feeding chamber 75, and then, the gate valve 78 is closed. Thus, a loading operation of the semiconductor wafer is completed, and a predetermined processing is carried out to the semiconductor wafer 100. If the predetermined processing is completed, the processed semiconductor wafer 100 is removed from the processing chamber 73 through the feeding chamber 76 and the load lock chamber 76 by an unloading operation in which respective steps of the above mentioned loading operation of the semiconductor wafer are conducted in inverse order.
Next, a detail of the processing chamber 73 and a wafer handling sequence carried out within the processing chamber 73 will be described with reference to FIGS. 2 and 3, which diagrammatically illustrate a parallel plate type, single-wafer-processing type dry etching machine, which is one type of semiconductor device manufacturing machine.
As shown in FIG. 2, the processing chamber 73 includes an upper electrode 81 and a lower electrode 82 for generating plasma therebetween, the stage 72 provided at the side of the lower electrode 82 and for supporting the semiconductor wafer 100 when the semiconductor wafer 100 is etched, a compensating ring 83 provided on a lower surface of the upper electrode 81 and formed to extend toward a periphery of the semiconductor wafer 100 for the purpose of compensating evenness in etching of the semiconductor wafer 100, and a plurality of lift pins 84 which can be vertically moved up and down in order to locate the semiconductor wafer 100 on the stage 72 and to maintain the semiconductor wafer 100 at a predetermined height from an upper surface of the stage 72 when the semiconductor wafer 100 is to be removed from the stage 72. The above mentioned construction is disclosed in for example Japanese Patent Application Laid-open Publication No. JP-A-62-128122.
On the other hand, as shown in FIG. 3, the holder 77 includes holding guides 771 for preventing the semiconductor wafer 100 put on the holder 77 from deviating from a proper position.
At the time of placing the semiconductor wafer 100 on the stage 72, the lift pins 84 are lifted to a top dead center, and in this condition, the holder 77 holding the semiconductor wafer 100 between the holding guides 771 is moved to a position directly above the stage 72. Then, the holder 77 is lowered until the semiconductor wafer 100 is placed on the lift pins 84 and an upper surface of the holder 77 becomes lower than an lower surface of the semiconductor wafer 100.
Thereafter, the holder 77 is retracted into the feeding chamber 75 from the position directly above the stage 72 within the processing chamber 73, and the lift pins 84 are lowered to a bottom dead center. Thus, the semiconductor wafer 100 is placed on the stare 72.
In the above operation, the holder 77 and the lift pins 84 are located not to interfere with each other. In addition, at the time of removing the semiconductor wafer 100 from the stage 72, respective steps of the above mentioned operation for placing the semiconductor wafer 100 on the stage 72, are conducted in inverse order.
As another example different from the above mentioned example, a chemical vapor deposition (CVD) machine, which is another type of semiconductor device manufacturing machine, comprises a holding plate for holding a semiconductor wafer, and another separate and removable holding plate configured to cover a periphery of the semiconductor wafer. This construction is disclosed by for example Japanese Patent Application Laid-open Publication No. JP-A-2-130819.
At the time of carrying out a predetermined chemical vapor deposition on the semiconductor wafer, the semiconductor wafer is placed on the holding plate. At this time, the vapor deposition occurs not only on the semiconductor wafer but also on the removable holding plate covering the periphery of the semiconductor wafer. As a result, a reaction product film deposited on the removable holding plate becomes particles, which adhere to the semiconductor wafer, with the result that the production yield of the manufacturing machine drops. Therefore, the removable holding plate is periodically exchanged with a new one.
In the above mentioned conventional semiconductor device manufacturing machines and the methods for manufacturing the semiconductor device by using the manufacturing machines, reaction products deposit on or adhere to a peripheral member located at the periphery of the semiconductor wafer in the processing chamber (for example, the compensating ring in the parallel plate type, single-wafer-processing type dry etching machine and the holding plate in the chemical vapor deposition machine), or alternatively, the peripheral member itself is etched. Therefore, it is necessary to clean or exchange the peripheral member by bringing the processing chamber maintained in a vacuum condition, into an atmospheric pressure.
Specifically, in the parallel plate type, single-wafer-processing type dry etching machine, the peripheral member, namely, the compensating ring is exposed to a plasma atmosphere, and therefore, is etched so that a shape of the compensating ring is damaged or lost. As a result, the compensating ring, which had properly compensated a plasma distribution, can no longer properly compensate the plasma distribution after being used for a certain length of time. The evenness of etching to the semiconductor wafer is deteriorated, and therefore, the yield of production in the semiconductor device manufacturing machine drops. Accordingly, in order to prevent this drawback, it is necessary to replace the compensating ring which was used for a certain length of time, by a new one.
On the other hand, in the case in which a surface temperature of the compensating ring is lower than that of the other portions in order to obtain a desired process performance and a plasma atmosphere uses a gas apt to cause deposition (for example, CHF.sub.3), deposition occurs on the surface of the compensating ring. However, it is impossible to completely prevent this deposition, even if there exists a method of reducing the deposition. As a result, a thickened deposition peels off from the compensating ring and adheres to the semiconductor wafer surface. Thus, the yield of production in the semiconductor device manufacturing machine drops. In this case, similarly, it is necessary to replace the compensating ring which was used for a certain length of time, by a new one, or to provide a means for removing the deposition.
Furthermore, in the chemical vapor deposition machine or a sputtering machine, as mentioned above, deposition occurs not only on the semiconductor wafer but also on the holding plate located in proximity of the semiconductor wafer, so that the thickness of the holding plate increases, with the result that a thickness of the film deposited on a peripheral region of the semiconductor wafer becomes smaller than that of the film deposited on a center region of the semiconductor wafer. Namely, the evenness of the thickness of the deposited film is deteriorated. In addition, the film deposited on the holding plate drops on the semiconductor wafer surface in the form of particles. Thus, even in this case, the yield of production in the semiconductor device manufacturing machine drops. Accordingly, it is necessary to periodically remove the deposition or to periodically exchange the holding plate.
However, in order to exchange a component or clean the component, it is necessary that, before the exchange or cleaning of the component, the processing chamber which was maintained at a predetermined vacuum level is brought into an atmospheric pressure, and after the exchange or cleaning of the component is completed, the processing chamber is returned to the predetermined vacuum level, again. This lowers an operating efficiency of the manufacturing machine.